Question

Calculati sin 135' -sin 45'

Answer 1

$\displaystyle \sin \ 135-\sin \ 45=\sin(90+45)-\sin \ 45= \\ \\ =\sin \ 90*\cos \ 45+\sin \ 45*\cos \ 90-\sin \ 45= \\ \\ =1*\frac{\sqrt2}{2}+\frac{\sqrt2}{2}*0-\frac{\sqrt2}{2}=\frac{\sqrt2}{2}+0-\frac{\sqrt2}{2}=0\end{math}$

Answer 2

sin135°-sin45°=sin(180°-45°)-sin45°=sin45°-sin45°=0